We investigate the relationship which exists between certain classes of ordered small
categories, introduced by Charles Ehresmann in the course of his work on local structures …

Let Singn be the subsemigroup of singular elements of the full transformation semigroup on
a totally ordered finite set with n elements. Let be the subsemigroup of all decreasing maps …

In this paper we will study the properties of a natural partial order which may bedefined on
an arbitrary abundant semigroup: in the case of regular semigroups werecapture the order …

The investigation of general quasi-adequate semigroups is initiated. These are semigroups
which are abundant and in which the idempotents form a subsemigroup. For such a …

Abundant semigroups with a multiplicative type A transversal Page 1 Semigroup Forum Vol. 47
(1993) 327-340 9 1993 Springer-Verlag New York Inc. RESEARCH ARTICLE Abundant …

Let In be the symmetric inverse semigroup on Xn={1,…, n}, let Sln be the subsemigroup of
strictly partial one-to-one self-maps of Xn and let={α∊ SIn: x}≦ x= U=∅= be the semigroup of …

The relations 2” and. 3!* are generalisations of Green's relations 9 and 9: elements a and b
of a semigroup S are related by. P*(%?*) in S if and only if they are related by A?(2) in some …

Congruences on an ample semigroup S are investigated. For any admissible congruence ρ
ρ on S, the minimum σ _ ρ σ ρ (the maximum μ _ ρ μ ρ) admissible congruence on S whose …

In this paper, the translational hull of a type-A semigroup is considered. Our main result is to
prove that the translational hull of a semilattice of cancellative monoids (respectively a …

The aim of this paper is to investigate abundant semigroups with a multiplicative adequate
transversal. Some properties and characterizations for such semigroups are obtained. In …